1. Field of the Invention
This invention relates to certain 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxides and to certain 3,3-disubstituted-2,3-dihydronaphtho[1,8-de]-1,2-thiazine-1,1-diox ides useful in the preparation of phenol and 1-naphthol sulfamphthaleins and sulfamnaphthaleins and to the preparation of said 3,3-disubstituted compounds.
2. Description of the Prior Art
Various procedures have been reported for synthesizing 3-disubstituted-benz[d]isothiazole-1,1-dioxides and 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxides from saccharin (3-oxo-2,3-dihydrobenz[d]isothiazole-1,1-dioxide) and from saccharin pseudo-chloride (3-chlorobenz[d]isothiazole-1,1-dioxide). As reported by A. Mustafa et al, J. Chem. Soc., 1952, p. 1339, the treatment of saccharin pseudo-chloride with excess phenylmagnesium bromide gave the corresponding 3,3-diphenyl-2,3-dihydrobenz[d]isothiazole-1,1-dioxide in almost quatitative yield. Methyl-, ethyl-, n-propyl- and n-butylmagnesium halides were reported by these authors to react analogously. R. A. Abramovitch et al, J. Chem. Soc., Perkin Trans I, 1974(22), p. 2589, reviewed and reinvestigated the reactions of saccharins with alkyl and aryl Grignard reagents and found that either the 3-alkyl (or 3-aryl)-benz[d]isothiazole-1,1-dioxide and/or the open-chain tertiary alcohol, o--CR.sub.2 OH benzenesulfonamide wherein R is alkyl (or aryl) were obtained with one exception. When saccharin was treated with an excess of phenylmagnesium bromide in boiling tetrahydrofuran, 3,3-diphenyl-2,3-dihydrobenz[d]isothiazole-1,1-dioxide was obtained as the minor product together with the open-chain tertiary alcohol.
R. A. Abramovitch et al also investigated the reaction of saccharin and saccharin pseudo-chloride with organolithium compounds and found that the reaction of saccharin with alkyl- and aryllithium compounds, such as, n-butyllithium and p-methoxyphenyllithium in tetrahydrofuran at -78.degree. C. gave the corresponding 3-substituted-benz[d]isothiazole-1,1-dioxide, exclusively. In addition to this general method for synthesizing 3-alkyl (or 3-aryl)-benz[d]isothiazole-1,1-dioxides, the authors reported that the reaction of the pseudo-chloride with organolithium compounds, such as, n-butyllithium in tetrahydrofuran at -78.degree. C. gave the corresponding 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxide as the major product.
Besides the reactions with Grignard and organolithium reagents, Friedel-Crafts reactions with the saccharins also have been disclosed. Dutt, J. Chem. Soc., 121, p. 2389 (1922) reported the condensation of saccharin with aromatic amines and phenols in the presence of concentrated sulfuric acid and also in the presence of fused zinc chloride. The resulting condensation products with saccharin were named "sulfamphthaleins" by analogy to "phthaleins" and "sulfonephthaleins". Though the structure of 3,3-di(4'-hydroxyphenyl)-2,3-dihydrobenz[d]isothiazole-1,1-dioxide (named "phenolsulfamphthalein") was assigned to the condensation product obtained with saccharin and phenol, it has been determined that the compound corresponding to the proposed structure has properties different from those reported, for example, colorless rather than pink in alkali and also, that the compound corresponding to the structure given could not be synthesized by repeating the procedures reported by Dutt.
Copending U.S. patent application Ser. No. 836,010 of Stanley M. Bloom, Alan L. Borror and James W. Foley filed concurrently herewith is directed to a method of synthesizing phenol and 1-naphthol sulfamphthaleins and sulfamnaphthaleins possessing a carbonyl group in the 2-position of the sulfam(na)phthalein ring. Depending upon the carbonyl group and the phenolic and/or naphtholic substituents, the products of the synthesis may be employed as pH-sensitive indicator dyes, antihalo dyes or photographic optical filter agents. As disclosed and claimed therein, the method of preparing these compounds comprises reacting a 3-(4'-OP-carbocyclic aryl)-3-(carbocyclic aryl)-2,3-dihydrobenz[d]isothiazole-1,1-dioxide (or -2,3-dihydronaphtho[1,8-de]-1,2-thiazine-1,1-dioxide) wherein P is a protecting group with a carboxylic acid halide to yield the corresponding 2-carbonyl derivative followed by removing the protecting group with weak acid to yield the product. In the compounds prepared by this method, one of the 3,3 substituents is a 4'-hydroxycarbocyclic aryl moiety and the other may be the same or different.
The present invention is concerned with 3,3-di(4'-OP-carbocyclic aryl)-2,3-dihydrobenz[d]isothiazole-1,1-dioxides (and -2,3-dihydronaphtho[1,8-de]-1,2-thiazine-1,1-dioxides) useful as starting materials in the aforementioned synthesis and to the preparation of said isothiazole and said 1,2-thiazine-1,1-dioxides.